Apparatus, systems and methods for cross track error calculation from active sensors

ABSTRACT

The disclosed apparatus, systems and methods relate to determining cross track error between a stored planted location and the actual physical location of plants. An array of active light sensors is mounted on a vehicle for travel above the plants. The array of active light sensors generate an electrical signal from each sensor corresponding to the reflected light from the sensor. A computer system generates a reflectance curve from the array of sensors to determine the location of a plant below the array of sensors and also generates the cross track error.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No. 14/823,525, filed Aug. 11, 2015, which claims priority to U.S. Provisional Application No. 62/035,590, filed Aug. 11, 2014, both of which are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The disclosed technology relates generally to devices, systems and methods for system for determining cross track error and in particular, to the devices, methods, and design principles allowing the use of sensing systems, such as light and mechanical sensing systems, to compare the actual location of plants with stored locations of plant. This has implications in many agricultural industries.

BACKGROUND

The disclosure relates to apparatus, systems and methods for determining cross track error.

Current guidance systems assume that guidance lines created with GPS are a true reflection of the actual planting lines. Reducing error from GPS drift by adding options such as Real-time kinematic (RTK) correction will help create a very repeatable guidance line, but does not take into account the small errors that occur during the planting or application process. If there is an accidental shift during planting, the guidance line will indicate the rows were planted straight, but the plants will emerge shifted.

Additionally, GPS units may track slightly differently between GPS units creating a slightly different guidance line placement between planter and application equipment. Each of these instances of variation from the calculated guidance line would be corrected by a sensor controlled guidance line which responds to the plant location rather than assume planted location.

Many sidedress applicators know of these issues and choose to manually guide the equipment through the field rather than let an error in GPS guidance destroy a large section of their plants. The problem with this is human error can also cause incidental drift which will also lead to damage of plants.

U.S. Pat. No. 5,585,626 divulges the idea of using light sensors for guidance assistance, but does not provide any details on how to determine actual row location.

Current systems calculate cross track error based on where it is assumed the rows will be at. Using light sensors, the cross track error will be created from accurate measurements of the physical location of the plant row.

BRIEF SUMMARY

Discussed herein are various devices, systems and methods relating to an array of active light sensors mounted on an agricultural vehicle and an associated computer system for detecting the actual location of plants in a row and computing the difference between the actual row location from the location generated during planting using a GPS system. The array of active light sensors and associated computer system determines the location of a plant in a row by identifying a peak reflectance value which corresponds to the center of the plant. The sensors and associated computer system are able to distinguish desired crop plants from foreign vegetation, such as weeds, and to disregard sensor readings from the foreign vegetation. The sensors and associated computer system are able to distinguish between soil and vegetation readings and disregard soil readings so as to identify rows of plants and to disregard sensor readings of temporary abrupt changes in vegetation location that are caused by unintended seed placement or errant plant growth.

The sensors and associated computer system are, in certain Examples, interconnected with an automatic steering system to steer an agricultural vehicle along the path of the actual row of plants or to a parallel GPS manual guidance system to assist in guiding the operator along the path of the actual row of plants.

In another Example, the sensors and associated computer system can more accurately detect the path of the plants compared to the direction of travel of the vehicle by using at least two sensor arrays over the same rows. The system would be able to more quickly respond to changes in path direction by calculating the difference in location between a front mounted and rear mounted array. The system could then predict the path direction very near to the current location of the vehicle, which is especially useful for detecting when rows of plants start to curve.

In another Example, the sensors and associated computer system use an array of active light sensors mounted on a vehicle to determine the lateral position of vegetation relative to a ground engaging member of the vehicle and determines a crow-track driving error.

While multiple embodiments are disclosed, still other embodiments of the disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosed apparatus, systems and methods. As will be realized, the disclosed apparatus, systems and methods are capable of modifications in various obvious aspects, all without departing from the spirit and scope of the disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an array of sensors scanning a single plant to create a reflectance curve, according to one implementation.

FIG. 2 is a schematic diagram of an array of sensors used to find the gap between rows by comparing reflectance curves, according to one implementation.

FIG. 3 is a further schematic diagram of the implementation of FIG. 1, showing a block diagram of the vehicle control systems.

FIG. 4 is a further schematic diagram of the implementation of FIG. 2, showing a block diagram of the vehicle control systems.

DETAILED DESCRIPTION

As shown in the implementations of the calculation device, method and system 10 shown in FIGS. 1 and 3, an array 12 of active light sensors 16 is passed over a growing plant 16. Each sensor in the array 12 measures a reflectance value when it is over a part of the plant 16. The reflectance values are compiled to form a reflectance curve of the plant biomass. This reflectance curve is used in a variety of ways to determine cross track error from accurate measurements of the physical location of the plant row and to assist in guidance of an agricultural vehicle on which the array is mounted as it passes through a field of crops.

In the implementation of the calculation device, method and system 10 shown in FIGS. 2 and 4, there is illustrated apparatus comprising an array 12 of sensors 14 that are used to find the gap between rows. If a crop type has little to no peak reflectance value at the center of the plant, sensors 14 can be used to indicate the total area of two plants. Knowing the gap between rows based on planter spacing, the system can calculate the center of the gap between rows to create a cross track error from.

In these and other implementations, the vehicle 20 has a computer system 22 configured to calculate a cross track driving error by determining the lateral relative position of vegetation as measured by the sensors to a ground engaging member of the vehicle 20. The computer system 22 includes a storage device 24, module or other device configured to store a Zero Error Position on the sensor array 12 that defines the vehicle is traveling the desired path whenever vegetation is passing under Zero Error Position. The computer system 22 also is used to determine the direction of cross track vehicle driving error by comparing the position on the active light sensor array 12 that vegetation is passing under to the Zero Error Position is used to determine the magnitude of cross track vehicle driving error by comparing the position on the active light sensor array that vegetation is passing under to the Zero Error Position, for example by adding the spacing between light sensors on said sensor array from where vegetation is passing under array to the Zero Error Position. In an exemplary embodiment, a display 26 is used to show an operator of the vehicle 20 the direction and magnitude of cross track vehicle driving error.

In another embodiment, the computer system 22 is interconnected with an automatic steering system 28 and uses the direction and magnitude of cross track vehicle driving error to automatically steer vehicle down a desired path. In this embodiment, a further refinement automatically determines when the cross track driving error from the active light sensor array 12 is sufficiently accurate to automatically engage steering.

In another embodiment, the computer system 22 accepts and uses a manual input to compensate direction and magnitude of cross track vehicle driving error for changes in vegetation biomass. For example, the manual input can be a user entered vegetation biomass parameter (e.g. growth stage, plant height).

In another embodiment, the computer system 22 automatically compensates the direction and magnitude of cross track vehicle driving error for changes in vegetation biomass using an algorithm that compensates for changing biomass by interpreting sensor signals without any user entered vegetation biomass parameters except for crop type.

A particular application of the disclosed implementations is detecting cross track driving error with the active light sensor array mounted to a vehicle used to detect the middle of a row space between adjacent rows; that is, using the array to identify adjacent rows of plants and calculating the line of halfway points. In another application of the disclosed implementations, the active light sensor array mounted on a vehicle is used to augment the cross track driving error of a parallel GPS manual guidance or automatic steering system, and may include comparing active light sensor readings to a GPS readings of a parallel guidance line system and/or comparing active light sensor readings of one row of crop to another row of crop sensed by the active light sensor array.

In another embodiment, the active light sensor readings from vegetation are compared to a mechanical row feeler system 30.

The disclosed implementations can be used to determine a cross track driving error by using the active light sensor array system to detect the location plants and compare it to the stored row spacing as planted, as well as verifying the location of two or more rows or one or more row spaces by comparing detected row space to actual planted row spacing.

The disclosed implementations can also be used to detect cross track driving error with the active light sensor array mounted on a vehicle by computing a rolling average of sensor readings in the direction of travel or, alternatively, computing an average from two or more sensors laterally positioned relative to the direction of travel.

The disclosed implementations can also be used to detect cross track driving error with an active light sensor array where system compensates for one or more wind parameters, such as wind speed and wind direction. In one such embodiment, the wind parameter is measured in real time on the vehicle 20 via a detection system 32 and wherein an algorithm uses the combination of wind parameters and sensor data to detect a row offset distance correction for cross track driving error.

The disclosed implementations can also be used to detect GPS drift based on plant row location compared to GPS created guidance line location. The invention shifts the GPS created guidance lines to the corrected location based on the location of the vehicle relative to the crop rows. In a preferred embodiment, an algorithm calculates a temporary correction for the guidance from a GPS created guidance line based on the sensor array detection of shifts in the plant rows.

The disclosed implementations can also be used to more accurately detect the path of the plants compared to the direction of travel of the vehicle by using at least two sensor arrays 12A, 12B over the same rows, as is shown in FIGS. 3-4. In this arrangement, the system 10 is able to more quickly respond to changes in path direction by calculating the difference in location between a front mounted and rear mounted array. The system 10 is thereby able to predict the path direction very near to the current location of the vehicle, which is especially useful for detecting when row of plants start to curve.

The disclosed implementations can also be used to correct cross track driving error for vegetation on slopes that do not grow perpendicular to soil surface by using slope readings from a real time slope sensor on the vehicle.

In various implementations, the cross track driving error of a mounted or drawn implement is determined for the purpose of either passively or actively steering the implement equipment.

The sensors preferably have a narrow and defined viewing area to determine an accurate amount of biomass directly in the viewing area of the sensor. The sensors also preferably sample data at a very high rate, even more preferably above 100 Hz.

The foregoing description and drawings comprise illustrative embodiments of the disclosed implementations. The foregoing embodiments and the methods described herein may vary based on the ability, experience, and preference of those skilled in the art. Merely listing the steps of the method in a certain order does not constitute any limitation on the order of the steps of the method. The foregoing description and drawings merely explain and illustrate the invention, and the invention is not limited thereto, except insofar as the claims are so limited. Those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the scope of the invention.

Although the disclosure has been described with reference to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the disclosed apparatus, systems and methods. 

What is claimed is:
 1. A system for determining cross track error, comprising: a. at least one active light sensor array suspended on a vehicle; b. a computer system comprising a processor in operational communication with the at least one active light sensor array, wherein the processor is configured to: i. establish an actual plant position from the at least one active light sensor array, and ii. compare the actual plant position with a stored plant position to determine cross-track error; and c. a ground-engaging member, wherein the processor is configured to calculate a cross-track driving error by determining a lateral relative position of vegetation.
 2. The system of claim 1, wherein the processor is further configured to: a. generate a reflectance curve, and b. establish the actual plant position from the reflectance curve.
 3. The system of claim 1, wherein the computer system comprises a storage device configured to store a zero error position on the sensor array.
 4. The system of claim 1, wherein the zero position error defines a desired vehicle path.
 5. The system of claim 4, wherein the vehicle comprises an automatic steering system operationally integrated with the computer system and configured to receive the desired vehicle path.
 6. The system of claim 1, wherein the processor is configured to establish a direction of cross-track driving error.
 7. The system of claim 1, wherein the processor is configured to establish a magnitude of cross-track vehicle driving error.
 8. A cross-track error detection device for a vehicle, comprising: a. at least one actual plant position sensor comprising at least one light sensor and at least one mechanical sensor; and b. a computer system comprising a processor and memory, wherein: i. the memory is configured to store a stored plant position, ii. the at least one actual plant position sensor is configured to establish an actual plant position, and iii. the computer system is operationally integrated with the at least one actual plant position sensor and configured to determine cross-track error by comparing the actual plant position to the stored plant position.
 9. The cross-track error detection device of claim 8, wherein the computer system is operationally integrated with an automatic steering system.
 10. The cross-track error detection device of claim 9, wherein the computer system is configured to establish: a. a direction of cross-track driving error; b. a magnitude of cross-track vehicle driving error; and c. a zero error position.
 11. The cross-track error detection device of claim 9, wherein the computer system is configured to establish a zero position error and a desired vehicle path for the automatic steering system.
 12. The cross-track error detection device of claim 9, wherein the vehicle comprises an automatic steering system operationally integrated with the computer system and configured to receive a desired vehicle path.
 13. A cross-track error detection device for a vehicle with an automatic steering system, comprising: a. at least one light sensor; b. at least one mechanical sensor; and c. a computer system comprising a processor and memory, wherein: i. the memory is configured to store a stored plant position, ii. the processor is configured to establish an actual plant position from the at least one light sensor or the at least one mechanical sensor, and iii. the computer system is configured to determine cross-track error by comparing the actual plant position to the stored plant position and operationally integrated with the automatic steering system.
 14. The cross-track error detection device of claim 13, wherein the computer system is configured to generate a reflectance curve from the at least one light sensor.
 15. The cross-track error detection device of claim 13, wherein the computer system is configured to establish a zero error position.
 16. The cross-track error detection device of claim 15, wherein the computer system executes an algorithm configured to compensate for changing biomass by interpreting signals from the at least one light sensor and the at least one mechanical sensor.
 17. The cross-track error detection device of claim 13, wherein the at least one light sensor is an active light sensor array.
 18. The cross-track error detection device of claim 13, wherein the computer system is configured to accept and use a manual input to compensate direction and magnitude of cross track vehicle driving error.
 19. The system of claim 1, wherein the stored plant position is a guidance line.
 20. The cross-track error detection device of claim 8, wherein the stored plant position is a guidance line.
 21. The cross-track error detection device of claim 13, wherein the stored plant position is a guidance line. 